Method of fabricating a polymer dispersed liquid crystal panel with measuring thickness, adjusting then hardening

ABSTRACT

An empty cell is produced by adhering an array substrate and a counterelectrode substrate with a sealant resin of a predetermined height. A mixture liquid comprising liquid crystal and a polymerizable photosetting resin is injected into the empty cell. Then, the cell is interposed between a flat rigid bench and a flat rigid plate, and the mixture liquid is heated to make it transparent. Then, the thickness of the mixture liquid is measured with an interferometer. If the measured thickness deviates from a predetermined range, the flat rigid plate is pressed until the measured thickness changes into the predetermined range. Then, the mixture liquid is irradiated to form a liquid crystal/resin composite layer. Then, the pressure is removed. Thus, a liquid crystal/resin composite layer of uniform thickness can be obtained.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of fabricating a liquidcrystal panel including a liquid crystal/resin composite layer as alight modulation layer.

2. Description of the Prior Art

A display device employing a liquid crystal display panel has beenstudied and developed widely because of its compact size and its lightweight. Recently, pocket television sets employing a twisted nematic(TN) mode liquid crystal display panel have been used practically.Furthermore, image projection type television systems, view finders, andthe like using the liquid crystal display panel as a light bulb havealso been used practically.

However, a TN mode liquid crystal display panel has disadvantages suchas low brightness of display due to the two polarization plates neededfor light modulation. Further, fabrication steps are complex. Forexample, rubbing is needed in order to align liquid crystal molecules.

Recently, liquid crystal panels with use of liquid crystal/resincomposite have attracted attention because it need no polarizing platesand no rubbing step on fabrication. A liquid crystal/resin composite isa composite of a liquid crystal component and a resin component, and theliquid crystal component extends in the matrix made of the resin(polymer) component. The structure of the liquid crystal/resin compositechanges according to the ratio of the liquid crystal component to theresin component, and it is classified typically into two types accordingto the ratio of the liquid crystal component to the polymer (resin)component. In one type of the composite having a small ratio of theliquid crystal component, droplets of liquid crystal are dispersed inthe voids of the resin layer, and the liquid crystal existsdiscontinuously, as shown schematically in FIGS. 1(a) and 1(b). Thistype is called as polymer dispersed liquid crystal. If the amount of theliquid crystal component is increased, droplets contact with each otherto form a continuous phase. In the other type having a large ratio ofthe liquid crystal component, a network of the resin component is formedand the liquid crystal exists not as droplets, but extends in thenetwork continuously. This structure is analogous to a spongeimpregnated with liquid crystal. This type is called as polymer networkliquid crystal.

The above-mentioned two types of liquid crystal/polymer composite can beused to display an image by controlling the scattering and transmissionof light. A display panel with use of the polymer dispersed liquidcrystal uses a property that the refractive index of the liquid crystalvaries with the orientation direction of the liquid crystal molecules.FIG. 1(a) shows schematically a polymer dispersion liquid crystal layer136 interposed between two substrates 131 and 132 each having thin filmtransistors 134 and pixel electrodes 135 and a counterelectrode 133. Thepolymer dispersion liquid crystal 136 comprises liquid crystal droplets141 in the resin matrix 142. Without applying a voltage to the liquidcrystal 136, the liquid crystal molecules in the droplets 141 align inirregular directions, as shown in FIG. 1(a). In this state, a differencein refractive index exists between the liquid crystal droplets 141 andthe resin 142 to scatter the incident light. By applying a voltage tothe liquid crystal 136, the liquid crystal molecules are aligned in adirection, as shown in FIG. 1(b). If the refractive index of the liquidcrystal component oriented in the direction is controlled preliminarilyto coincide with that of the resin component, the incident light is notscattered in the liquid crystal, but transmits through it. On the otherhand, the polymer network liquid crystal uses the irregularity itself ofthe orientation of the liquid crystal molecules for scattering thelight. In the irregular orientation state, or without applying a voltageto the liquid crystal, the incident light is scattered through theliquid crystal, while when the molecules align in a direction byapplying a voltage to the liquid crystal, the light transmits throughthe liquid crystal. The above-mentioned liquid crystal/resin compositedoes not need a polarizer and an analyzer for modulating the light.Therefore, it can display an image at a high luminance by twice or morewhen compared with a display panel with use of a twisted nematic liquidcrystal.

U.S. Pat. No. 4,435,047 disclosed a prior art fabrication method of aliquid crystal panel including a liquid crystal/resin composite. Amixture liquid comprising a nematic liquid crystal and a polyvinylalcohol (PVA) as a polymer is applied to an electrode substrate with aprint technique, and it is interposed between the substrate and acounterelectrode substrate. However, it is difficult to realize auniform thickness of liquid crystal by using the print technique, sothat the scattering of brightness arises in the display image of theliquid crystal panel. Further, because the polyvinyl alcohol is awater-soluble polymer, the water resistance is bad and the liquidcrystal panel becomes white and swells. Further, it need a long time toset the resin.

Japanese Patent laid open Publication 3-58021/1991 discloses a liquidcrystal panel with a liquid crystal/resin composite. Two electrodesubstrates are arranged so as to oppose the electrodes each other, andspacers such as beads are scattered between the two substrates. Theperiphery of the two substrates are sealed with an epoxy sealant exceptan injection hole to complete an empty cell. Then, a mixture liquidcomprising a liquid crystal and uncured resin is injected through theinjection hole and the injection hole is sealed. Then, ultraviolet raysirradiate the mixture liquid to set the resin so as to separate theresin from the liquid crystal.

In the above-mentioned liquid crystal panel, and uniform thickness ofthe liquid crystal/resin composite is realized because spacers such asbeads are used, and the brightness is also uniform in the display areadue to the spacers. However, the beads 137 also exist in the displayarea as shown in FIG. 2, and this causes a problem. A liquidcrystal/resin composite 136 has a thickness enough to scatter lightsufficiently, while if the thickness becomes high, a higher electricvoltage is needed to make the composite layer transparent. Usually, thethickness of the composite layer 136 is selected to be about 15 μm. Onthe other hand, the size of a pixel in the display area in a liquidcrystal panel has a tendency to become smaller. For example, if thedisplay area is three inches square and includes about 300,000 or1,000,000 pixels, a pixel occupies an area of about 100 or 50 μm square.Even if the area of a pixel is small, the thickness of the liquidcrystal/resin composite layer has to be as high as about 15 μm. If beads137 of about 15 μm of diameter are used, the light transmits beads 137which occupy spaces in the display area. Because the size of the beads137 is not so small as compared with the size of a pixel such as 50 μm,the light transmitting the beads 137 in the display area or the beads137 do not modulate the light and remains as white points which areremarkable in the display area. This deteriorates the display qualityespecially pixels of small area.

There is another fabrication technique to form bank-like supporters onthe source lines for applying an electric voltage to the pixels(Japanese Patent laid open Publication 4-84121/1992). If this techniqueis applied to a liquid crystal/resin composite panel, the height of thebank-like supporters have to be as high as about 15 μm. However, it isdifficult to form such supporters of 15 μm height by using thepatterning technique. Further, even if such supporters can be formed, itis difficult to inject a mixture liquid inside the supporters.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method of fabricatinga liquid crystal panel of a uniform thickness of liquid crystal layerwithout using beads.

In one aspect of the present invention of a method for to manufacturinga liquid crystal panel, a first electrode substrate and a secondelectrode substrate are provided, and a mixture liquid comprising aliquid crystal and monomers of a resin is filled between the first andsecond electrode substrates. Then, the thickness of the mixture liquidinterposed between the first and second electrode is measured. Then, themixture resin is hardened to separate into a liquid crystal portion anda resin portion. Thus, a liquid crystal/resin composite layer of a knownthickness can be prepared.

In another aspect of the present invention of a method for manufacturinga liquid crystal panel, a first electrode substrate and a secondelectrode substrate are provided. A support member of a predeterminedheight, say 15 μm, is arranged at the periphery of the first and secondelectrode substrates, and the first and second electrode substrate arefixed via the support member. Next, a mixture liquid comprising a liquidcrystal and monomers of a photosetting or thermosetting resin is filledin a space enclosed by the support member between the first and secondelectrode substrates, and the thickness of the mixture liquid interposedbetween the first and second electrode substrates is measured.Preferably, the photosetting resin comprises an ultraviolet-rays-resin.For a large liquid crystal panel, the thickness of the mixture may bedifferent at the center from the predetermined thickness determined bythe support member. Next, the thickness of the mixture liquid ismeasured and adjusted. The mixture liquid is opaque at room temperature.Then, the mixture liquid is heated to become isotropic or transparentand the thickness is measured in the transparent state with ainterferometer or the like. Then, if the measured thickness is outsidethe predetermined range, the thickness of the mixture liquid is changedwithin a predetermined range by changing the pressure applied to thesubstrates. The mixture resin is set with optical radiations orthermally to separate the mixture liquid into a liquid crystal portionand a resin portion while keeping the thickness within the predeterminedrange. Then, the pressure is removed. Because the resin becomes a solidpolymer, the thickness of the resultant liquid crystal/resin compositelayer can be kept uniform even for a wide liquid crystal panel.

An advantage of the present invention is that a liquid crystal panelwith a known thickness of a liquid crystal layer can be fabricated.

Another advantage of the present invention is that a liquid crystalpanel with a liquid crystal layer of a uniform thickness can befabricated even for a large display area.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention willbecome clear from the following description taken in conjunction withthe preferred embodiments thereof with reference to the accompanyingdrawings, and in which:

FIGS. 1(a) and 1(b) are schematic partial sectional views of a polymerdispersion liquid crystal under no applied electric field and under anapplied electric field, respectively;

FIG. 2 is a partial sectional view of a prior art liquid crystal panelincluding beads in display area;

FIG. 3(a), 3(b), 3(c), 3(d) and 3(e) are schematic sectional views ofsteps of fabricating a liquid crystal panel; and

FIG. 4 is a schematic elevational view of a liquid crystal panel underfabrication.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the several views, anembodiment of a fabricating method of a liquid crystal panel accordingto the present invention will be explained. Although the polymerdispersed liquid crystal panel is taken as examples in the followingembodiments for simplicity, either of the display panels using a polymerdispersed liquid crystal or a polymer network liquid crystal can be usedin the present invention.

FIGS. 3(a)-3(e) illustrate steps of fabrication a liquid crystal panel.First, an array substrate 31 and a counterelectrode substrate 32 areprovided. Pixel electrodes and thin film transistors (not shown forsimplicity) have been formed on the array substrate 31, while acounterelectrode (not shown) have been formed on the counterelectrodesubstrate 32. Then, a sealant resin 11 is applied to the periphery of adisplay area of the array substrate 31 or the counterelectrode substrate32. The sealant resin 11 includes fibers, beads or the like in order toattain a desired height. The height of the sealant resin 11 will agreewith that of liquid crystal in the liquid crystal panel eventually. Forexample, if the desired thickness of liquid crystal is 15 μm, beads of15 μm of diameter of the like are added. The beads or the like are notdistributed in the display area in contrast to prior arts. It ispreferable that the sealant resin 11 is an ultraviolet-rays-settingresin. After applying the sealant resin 11, the substrates 31 and 32 areadhered to each other, as shown in FIG. 3(a), and the sealant resin 11is hardened by irradiated with ultraviolet rays. The obtained liquidcrystal cell without liquid crystal is called as an empty cell.

Next, a mixture liquid 12 comprising a liquid crystal and apolymerizable resin before polymerization (an uncured resin) isprepared, and the mixture liquid 12 is injected into the empty cell withuse of a pressure injection technique. That is, the mixture liquid 12 isinjected under pressure into the empty cell through an injection hole 17of 1-2 mm of diameter provided at the periphery of the counterelectrodesubstrate 32, as shown in FIG. 3(b). On the other hand, if a vacuuminjection technique, after the space between the two substrates 31, 32is evacuated, the injection hole 17 is immersed in a mixture liquid 12to attract it into the empty space between the two substrates 31, 32.However, the vacuum injection technique is not appropriate for lightmodulation of good scattering characteristic because components such asmonomers splashes from the mixture liquid 12 when a vacuum state isrealized. In a modified example, the injection hole is not formed in thecounterelectrode substrate 32, and a part of the sealant resin 11 isremoved to use the remained section as an injection hole. The mixtureliquid 12 may have components for either of a polymer dispersed liquidcrystal or a polymer network liquid crystal of the liquid crystal/resincomposite.

Preferably, the liquid crystal component in the mixture liquid 12 is anematic liquid crystal, a smectic liquid crystal, or a cholestericliquid crystal. The liquid crystal may consist of a single compound or amixture of two or more liquid crystals, or a mixture further including asubstance other than liquid crystal compounds. Among the above-mentionedliquid crystal materials, cyanobiphenyl group nematic liquid crystalsare preferable because they have a large difference Δn of the anomalousrefractive index n_(e) from the normal refractive index n_(o).Preferably, the resin material is a transparent resin, and any ofthermoplastic resin, thermosetting resin, and photosetting resin may beselected. A photosetting resin such as an ultraviolet-rays-settingacrylic resin is preferable because it can be easily produced and wellseparated from the liquid crystal. Particularly, a resin is preferablewhich contains acrylic monomers or acrylic oligomers which can bepolymerized and set by ultraviolet ray irradiation. When a mixture ofsuch monomers with a liquid crystal material is irradiated withultraviolet rays, only the resin material reacts to form a polymer(resin), and the liquid crystal phase is separated from the resin phase.

A monomer used to prepare the polymer phase may be 2-ethylhexylacrylate, 2-hydroxyethyl acrylate, neopentyl glycol diacrylate,hexanediol diacrylate, diethylene glycol diacrylate, tripropylene glycoldiacrylate, polyethylene glycol diacrylate, trimethylol propanetriacrylate, pentaerythritol acrylate or the like. An oligomer orprepolymer for the polymer phase may be polyester acrylate, epoxyacrylate, polyurethane acrylate or the like.

In order to enhance the polymerization rate, a polymerization initiatormay be used such as a 2-hydroxy-2-methyl-1-phenylpropane-1-on (“Darocure1173” available from Ciba-Geigy Ltd.),1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-on (“Darocure 1116”available from Ciba-Geigy Ltd.), 1-hydroxy cyclohexyl phenylketone(“Irgacure 651” available from Merck) or the like. Furthermore, a chaintransfer agent, a photosensitizer, a dye, a crosslinking agent or thelike may be appropriately incorporated as an additional ingredient.

Further, the refractive index n_(p) in a state where the resin materialis set is made to agree roughly with the normal refractive index n_(o)of the liquid crystal. When an electric field is applied to the liquidcrystal layer, liquid crystal molecules are aligned in one direction tomake the refractive index of the liquid crystal to be n_(o) so as tomake the liquid crystal layer transparent. If the refractive index n_(p)is different largely from the normal refractive index n_(o), the liquidcrystal layer does not become transparent completely when an electricfield is applied to the liquid crystal layer, and the illuminance ofdisplay decreases.

The ratio of the liquid crystal component to the resin component in theliquid crystal/resin composite is generally 20 to 90 wt %, preferably50-80 wt %. If the ratio is less than 20 wt %, the amount of liquidcrystal droplets is small so that the effect of a change of therefractive index is small. On the other hand, if the ratio is more than90 wt %, there is a tendency that the resin component and the liquidcrystal component are separated from each other into top and bottomlayers, so that the ratio of the interface decreases to lower thescattering property of the liquid crystal layer. The structure of theliquid crystal/resin composite depends on the ratio. If the ratio isless than 50 wt %, the liquid crystal component exists as droplets,while it is 50 wt % or more, a continuous phase appears wherein theresin and liquid crystal components are tangled with each other.

The thickness of the liquid crystal layer is selected between 5 to 25μm, preferably 8 to 15 μm. If the thickness is too small, the scatteringcharacteristics is bad or the contrast is bad, while if the thickness istoo large, a high voltage drive is needed and the design of a drivecircuit for applying signals to pixel electrodes becomes difficult.

Preferably, the weight ratio of the liquid crystal is between 55 and 65weight percent or between 75 and 85 weight percent. Further, a ratio ofmonomers to oligomers is preferably between 5:5 and 6:4 if the weightratio of the liquid crystal is between 55 and 65 weight percent, orpreferably 9:1 and 8:2 if the weight ratio is between 75 and 85 weightpercent, in order to produce a liquid crystal layer of good scatteringproperties at a low voltage. More preferably, the weight ratio of theliquid crystal is about 60 weight percent and the ratio of monomers tooligomers is about 4:6.

After the above-mentioned injection of the mixture liquid shown in FIG.3(b), the array substrate 31 of the liquid crystal panel 16 fabricatedabove is put on a flat rigid bench 14, as shown in FIG. 3(c). The flatrigid bench means a bench which does not bend under pressure. Asexplained later, the flat rigid bench 14 is heated to a predeterminedtemperature to make the liquid crystal 11 transparent. The flat rigidbench 14 is for example a heater plate. Next, a flat rigid plate 13which can transmit ultraviolet rays covers the counterelectrodesubstrate 32. The flat rigid plate means a plate which does not bendunder pressure. The flat rigid plate 13 is a glass plate in thisembodiment. Alternately, the flat rigid plate 13 is a heater plate andthe flat rigid bench 14 is a glass plate.

Then, the mixture liquid 12 is heated with the heat generated by theheater plate 14 as illustrated schematically with arrows in FIG. 3(c).The mixture liquid 12 is in a white opaque state at room temperature. Ifthe mixture liquid 12 becomes transparent, the thickness of the mixtureliquid can be measured optically with a measuring equipment. Thetransition temperature to the isotropic or transparent state depends onthe species of the polymers and liquid crystal materials, and themixture liquid 12 is heated to become transparent sufficiently. Then,the thickness of the mixture liquid 12 in a display area of the liquidcrystal panel 16 is measured with a thickness measuring equipment 15, asshown in FIG. 3(d). Because the mixture liquid 12 is transparent, thethickness can be measured with a precision of 0.1 μm.

If the measured thickness deviates from a predetermined range, it isnecessary to adjust the thickness appropriately. FIG. 4 shows anadjuster for adjusting the thickness of the mixture liquid. Bufferrubbers 23a, 23b are put on the flat rigid bench 14 outside the liquidcrystal panel 16. A metal frame 21 is put above the buffer rubbers 23a,23b, and the flat rigid plate 13 is set at the center of the metal frame21. The height of the rubbers 23a, 23b is a little lower than the liquidcrystal panel 16 so as to provide a small gap between the flat rigidplate 13 and the liquid crystal panel 16. Three screws 22a, 22b and 22c(not shown) are provided at the metal frame 21 so as to press the liquidcrystal panel 16 through the flat rigid plate 13. It is preferable thatthe screws 22a, 22b and 22c have a pitch small enough to control theapplied pressure finely. A pressure controller other than screws, suchas a hydraulic cylinder may also be used. The mixture liquid 12 ispressed by applying a pressure above the flat rigid plate 13. Thethickness of the mixture liquid 12 is restricted to about the height ofthe sealant resin 11 by the existence of the sealant resin 11 at theperiphery. Further, by pressing the flat rigid plate 13 as mentionedabove, the thickness of the mixture liquid 12 becomes the same as theheight of the sealant resin 11 at the center of the display area.

Usually, the counterelectrode substrate 32 uses a glass substrate ofabout 1 mm of thickness. Because such a glass plate bends by a smallapplied pressure, the thickness of the mixture liquid 12 can becontrolled by the applied pressure. The thickness can be controlledunder monitor with the thickness measuring equipment 15 or the like. Thethickness measuring equipment 15 is for example an interferometer usedusually for measuring the thickness of liquid crystal layer. It ispreferable that the thickness is measured at several positions in thedisplay area simultaneously. If the diagonal length of the liquidcrystal panel 16 is about four inches, the thickness can be made uniformeven up to the center in the display area by controlling the pressure atthe three positions of the metal frame 21. However, if the diagonallength increases to about ten inches, the thickness at the center tendsto become larger. In this case, it is needed to add a mechanism to applya pressure at the central area. For example, a control screw is providedat the central area. When the thickness at the center of the displayarea becomes the predetermined value, the state under pressure is fixed.

If the thickness of the mixture liquid 12 at the center becomes smallerthan the predetermined value, it is needed to increase the thickness atthe center by pulling the flat rigid plate 13. For example, a sucker isset at the central area of the flat rigid plate 13 and it is pulled forincreasing the thickness up to the predetermined value.

Next, ultraviolet rays radiate the mixture liquid 12 from above theliquid crystal panel 16, as shown in FIG. 3(e), to polymerize themonomers in the mixture liquid 12. Thus, the liquid crystal phase isisolated from the resin component. The temperature control onpolymerization is important. The temperature is increased above thenematic to isotropic phase transition temperature which is usually about40° C. or higher. The ultraviolet rays are irradiated at an intensity of20-30 mW/cm² for two to eight minutes. The conditions on the temperatureand the intensity are determined with experiments by determining thephase diagram on the liquid crystal weight ratio and the temperature. Ifthe conditions are not appropriate, the grain sizes of liquid crystaldroplets and the like change with time, and the scattering propertiesare deteriorated. The applied pressure is removed after the irradiationfor polymerization. It is to be noted that because the resin componentin the mixture liquid becomes solid, the thickness of the obtainedliquid crystal layer 12 does not change further. This is acharacteristic of liquid crystal/resin composite. On the contrary, if aTN liquid crystal is used, the thickness changes back to the originalstate after the applied pressure for realizing the predeterminedthickness is removed.

The flat rigid plate 13 may be an opaque plate. In this case, the flatrigid bench 14 is made of a transparent material and the ultravioletrays are irradiated from the side of the bench 14. Thus, the presentinvention is not limited on the direction of radiation or on theirradiation technique.

The mixture liquid 12 may also be isolated into the solid and liquidphases by heating. In this case, the resin component comprises athermosetting resin.

In the above-mentioned fabrication method, the mixture liquid 12 isinjected between the counterelectrode substrate 32 and the arraysubstrate 31, and the thickness of the mixture liquid layer 12 issmoothed to be flat, and then the mixture liquid is polymerized to forma liquid crystal layer of uniform thickness. Therefore, it is easy tocontrol the thickness of the liquid crystal layer. Further, a step forscattering beads or the like is not needed in the fabrication method,and the steps in the fabrication method can be simplified, and the beadsare not distributed in the display area of the liquid crystal panel. Thethickness of about 15 μm of a liquid crystal panel including a liquidcrystal/resin composite is three times larger than that of a TN liquidcrystal panel. Therefore, if beads exist in the display area, thedisplay quality is deteriorated largely. In this embodiment, thisproblem is solved. The abovementioned embodiment is explained furtherwith reference to examples.

EXAMPLE 1

Pixel electrodes made of transparent indium tin oxide (ITO) and thinfilm transistors and the like are formed on an array substrate 31, whilea counterelectrode made of transparent ITO is formed on acounterelectrode substrate 32. The two substrates 31 and 32 are fixed soas to oppose the electrodes each other. A spacer 11 is made of a sealantresin of ultraviolet-rays-setting resin with dispersed glass fibers of13 μm of diameter. Next, ultraviolet rays irradiate the spacer 11 toproduce an empty cell.

Next, a mixture liquid 12 having materials of the weight ratio shown inTable 1 is prepared as a material for forming a liquid crystal/resincomposite. The nematic-isotropic phase transition temperature shown inTable 1 of the mixture liquid 12 is found to be 30.5° C. from the datameasured with a Mettler FP 900 thermoanalysis system.

TABLE 1 Components of mixture liquid Matrial Weight (g) Liquid crystal:BL002 8.200 (Merck Japan Co.) monomer: 2-ethylhexyl 0.600 acrylate(Nakarai Co.) 2-hydroxyethyl acrylate 0.600 (Nakarai Co.) oligomer:Biscoat 823 0.600 (Toagosei Chemical Industry Co.) polymerizationinitiator: 0.060 benzyldimethyl ketal (Nippon Kayaku Co.)

Next, the mixture liquid 12 is injected with the pressure injectiontechnique into the empty cell. The cell with the mixture liquid iscalled as liquid crystal panel below. The, the liquid crystal panel isput on the device illustrated in FIG. 4, and the thickness of themixture liquid is measured with a thickness measuring equipmentTFM-121AFT model of Orc Co. for measuring the thickness of mixtureliquid 12 while a pressure is applied on the glass substrate 32 to theliquid crystal panel at 40° C. in the isotropic state. This temperatureis not so high to cause a difference of the measured thickness from thethickness after the phase separation into the liquid crystal and theresin. The measurement is performed at four points in the display areaof the liquid crystal panel while the pressure is increased gradually.The pressure is fixed when the measured thickness at the four pointsbecome substantially the same as the thickness of the sealant resin 11of 13 μm. Then, ultraviolet rays irradiate the mixture liquid 12 at anintensity of 30 mW/cm² at the substrate surface for six seconds at atemperature of 50° C. Thus, a liquid crystal panel including a liquidcrystal/resin composite is completed. The liquid crystal panel is whiteuniformly in the whole display area under no applied electric field, anda uniform transparent state is realized by applying an electric field.

EXAMPLE 2

A mixture liquid 12 having materials of the weight ratio shown in Table2 is prepared as a material for forming a liquid crystal/resincomposite, and a liquid crystal panel is completed by using theabove-mentioned steps explained in Example 1. The nematic-isotropicphase transition temperature shown in Table 2 of the mixture liquid 12is found to be 27.1° C. from the data measured with the Mettle FP 900thermoanalysis system. The thickness is measured at 40° C. The completedliquid crystal panel is white uniformly in the whole display area underno applied electric field, and a uniform transparent state is realizedby applying an electric field.

TABLE 2 Components of mixture liquid Material Weight (g) liquid crystal:BL002 8.200 (Merck Japan Co.) monomer: 2-ethylhexyl 1.200 acrylate(Nakarai Co.) oligomer: Biscoat 823 0.600 (Toagosei Chemical IndustryCo.) polymerization initiator: 0.060 Darocure 1173 (Ciba-Geigy Ltd.)

EXAMPLE 3

A mixture liquid 12 having materials of the weight ratio shown in Table3 is prepared as a material for forming a liquid crystal/resincomposite, and a liquid crystal panel is completed by using theabove-mentioned steps explained in Example 1. The nematic-isotropicphase transition temperature shown in Table 1 of the mixture liquid 12is found to be 45.5° C. from the data measured with the Mettle FP 900thermoanalysis system. The thickness is measured at 50° C. The completedliquid crystal panel is white uniformly in the whole display area underno applied electric field, and a uniform transparent state is realizedby applying an electric field.

TABLE 3 Components of mixture liquid Material Weight (g) liquid crystal:BL002 6.200 (Merck Japan Co.) monomer: 2-hydroxyethyl 2.400 acrylate(Nakarai Co.) oligomer: MT-1200 1.400 (Toagosei Chemical Industry Co.)polymerization initiator: 0.060 benzyldimethyl ketal (Nippon Kayaku Co.)

Although the present invention has been fully described in connectedwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

What is claimed is:
 1. A method for manufacturing a liquid crystalpanel, which method comprising the steps of: providing a first electrodesubstrate and a second electrode substrate; adhering the first andsecond electrode substrate via a support member of a predeterminedheight provided at the periphery of first and second electrodesubstrates; providing a mixture liquid comprising a liquid crystal andpolymerizable a resin; filling the mixture liquid in a space inside thesupport member between the first and second electrode substrates;measuring the thickness of the mixture liquid interposed between thefirst and second electrode substrates; changing the thickness of themixture liquid within a predetermined range if the measured thickness isoutside the predetermined range; and hardening the mixture liquid toseparate the mixture liquid into a liquid crystal portion and a resinportion while keeping the thickness within the predetermined range. 2.The method according to claim 1, wherein said support member comprises asealant resin.
 3. The method according to claim 1, wherein in said stepof measuring the thickness, said mixture liquid is changed into atransparent state and the thickness is measured in the transparentstate.
 4. The method according to claim 3, wherein said mixture liquidis changed into a transparent state by heating the mixture liquid tobecome an isotropic state.
 5. The method according to claim 3, whereinin said step of measuring the thickness of said mixture liquid, thethickness is measured at a plurality of positions in a display area ofsaid liquid crystal panel.
 6. The method according to claim 3, whereinin said step of changing the thickness of the mixture liquid, a pressureis applied between said first and second electrode substrates.
 7. Themethod according to claim 1, wherein said resin is a photosetting resinand said mixture liquid is hardened by light radiations.
 8. The methodaccording to claim 1, wherein said liquid crystal comprises a nematicliquid crystal, said resin is a photo-setting resin, and the normalrefractive index of said liquid crystal is substantially equal to thatof said photosetting resin.
 9. The method according to claim 1, whereinsaid support member has a height substantially equal to the thickness ofsaid mixture liquid and said support member is located outside a displayarea of said liquid crystal between said first and second electrodesubstrates.
 10. The method according to claim 1, wherein a ratio ofliquid crystal in said mixture liquid is between 20 and 90 weightpercent.
 11. The method according to claim 10, wherein a ratio of liquidcrystal in said mixture liquid is between 50 and 85 weight percent. 12.The method according to claim 1, wherein the height of said supportmember is between 5 and 25 μm.
 13. The method according to claim 1,wherein said resin is a thermosetting resin and said mixture liquid ischanged into a liquid crystal/resin composite by heating.
 14. A methodfor manufacturing a liquid crystal panel, said method comprising thesteps of: providing a first electrode substrate and a second electrodesubstrate; providing a mixture liquid comprising a liquid crystal and apolymerizable resin; filling the mixture liquid between the first andsecond electrode substrates; measuring the thickness of the mixtureliquid in the isotropic state ; changing the thickness to within anallowable range if the measured thickness deviates from the allowablerange; and hardening the mixture resin to separate into a liquid crystalportion and a resin portion.
 15. The method according to claim 14,further comprising a step of changing the thickness within an allowablerange if the thickness measured in the measuring step deviates from theallowable range.
 16. A method for manufacturing a liquid crystal panel,said method comprising the steps of: providing a first electrodesubstrate and a second electrode substrate; providing a mixture liquidcomprising a liquid crystal and a polymerizable resin; filling themixture liquid between the first and second electrode substrates;heating the mixture liquid to form an isotropic state; measuring thethickness of the mixture liquid in the isotropic state; and hardeningthe mixture resin to separate into a liquid crystal portion and a resinportion.